Today's devotional in Oswald Chamber's "My Utmost For His Highest" is very good in explaining how someone can be born again and still not ACT like a believer should!
When a person is born again, there is a period of time when he does not have the same vitality in his thinking or reasoning that he previously had. We must learn to express this new life within us, which comes by forming the mind of Christ (see Philippians 2:5). Luke 21:19 means that we take possession of our souls through patience. But many of us prefer to stay at the entrance to the Christian life, instead of going on to create and build our soul in accordance with the new life God has placed within us. We fail because we are ignorant of the way God has made us, and we blame things on the devil that are actually the result of our own undisciplined natures. Just think what we could be when we are awakened to the truth!
There are certain things in life that we need not pray about— moods, for instance. We will never get rid of moodiness by praying, but we will by kicking it out of our lives. Moods nearly always are rooted in some physical circumstance, not in our true inner self. It is a continual struggle not to listen to the moods which arise as a result of our physical condition, but we must never submit to them for a second. We have to pick ourselves up by the back of the neck and shake ourselves; then we will find that we can do what we believed we were unable to do. The problem that most of us are cursed with is simply that we won’t. The Christian life is one of spiritual courage and determination lived out in our flesh.
The key to understand this is to realize that we are triune beings. We are spirits who possess souls and live in human bodies (1 Thessalonians 5:23)! At the New Birth our formerly dead human spirit is recreated in the image of God instantly (1 Corinthians 5:17). When Jesus appears for the Church, our formerly mortal bodies will be changed instantly into the same type of resurrected body that Jesus had (1 Corinthians 15:51-52). In the meantime, WE are responsible for recreating, renewing, and changing our souls (mind, emotions and will) to be in line with the Word of God (Romans 12:1-2). This does NOT happen instantly, but progressively as we spend time daily in the Word of God and in prayer, praise and worship and fellowship with Him! The Holy Spirit is the One Who BEGAN the good work in us the moment we were born again, and He is the One Who will continue working that good work in us, but WE must give Him something to work with! Make it YOUR determined purpose today to renew your mind to conform to the will of God, as revealed in the Word of God! You will NEVER regret that decision! Amen! Here is an older song by Hillsong called "From The Inside Out":
Shalom in Him!